This invention relates to arrangements for steering a motor vehicle having at least two steerable wheels which includes steering equipment for setting the position of the steerable wheels as a function of a desired steering signal and equipment for producing a steering response of the motor vehicle in the event of a fault in the steering equipment and to a method for steering a motor vehicle in which the setting of the position of the wheels in order to produce a steering response is carried out by steering equipment as a function of a desired steering signal.
In electric steering systems for motor vehicles, the so-called steer-by-wire systems, as disclosed, for example, in U.S. Pat. No. 5,247,441, are safety-critical equipment. In order to satisfy the high safety requirements for such equipment, subassemblies, for example control equipment or actuators for setting the positions of the steerable wheels, are provided in a redundant and therefore very complicated manner. Particularly in the case of electric steering systems in which the wheels are steered independently of each other and without being connected to each other, it is difficult to implement the actuators in a redundant manner for space reasons. In addition, such redundancy is also technically difficult to realize so that redundant systems are not readily available.
U.S. Pat. No. 5,134,352 discloses a vehicle steering response control device for a motor vehicle which has anti-skid braking equipment. In this system, the control equipment responds to a signal which represents the steering condition of a turning vehicle to produce a different braking force applied to the wheels lying on the inside of the curve and on the outside of the curve with the result that a yawing moment is produced between the wheels lying on the inside and on the outside, in order to support the steering of the vehicle during a braking procedure.